Chewing hot taco, he gets this pain (9)
I believe the answer is:
toothache
'this pain' is the definition.
(toothache is a kind of pain)
'chewing hot taco he' is the wordplay.
'chewing' indicates an anagram.
'hot'+'taco'='hottaco'
'hottaco' anagrammed gives 'toothac'.
'toothac'+'he'='TOOTHACHE'
'gets' acts as a link.
(Other definitions for toothache that I've seen before include "Dental pain" , "Odontalgia" , "Oral discomfort" , "It causes grief" , "Trouble with choppers" .)